British light heavyweight Buatsi earned a win yet unimpressive start to life under new promoters with a decision win over Parker in the Manchester arena.
The Olympic medal winner's punch output seemingly secured him a majority decision in a competitive ten-round bout at the Co-op Live Arena.
But the challenger landed significant shots, connecting with powerful clean blows in a match where the techniques failed to mesh, with excessive holding spoiling the contest.
The officials had it 96-94 in favor to Buatsi, with the remaining official a 95-95 draw.
"It wasn't my best showing but how do champions respond? They succeed," Buatsi stated in the arena as he was met by disapproval from the audience.
The British fighter bounced back after his maiden career setback - an memorable fight with his previous opponent in last winter - to claim a twentieth professional win.
Several boxing experts felt Parker, thirty-one, merited the decision but the British boxer endured the second setback of his 28-match professional journey.
The Champion Secures Win in Uneventful Match
The fighter's advancement has stalled in recent years through management issues and considerable time of lack of fights.
Earlier forecast as the future of the British fight scene, he now stands trying to achieve expectations - maybe in what appears to be a last chance - under fresh management.
He began cautiously, with the two boxers prepared to be aggressive in a calculated early stages.
The challenger, whose single earlier setback came at super-middleweight against his former opponent in two years ago after damaging his hand mid-fight, was making just his second appearance at light-heavyweight.
By the halfway stage, the underdog had stayed in contention, creating difficulties for Buatsi, who operated with a protective stance to barely take the better rounds.
The audience's tolerance decreased amid regular grabbing, with the challenger falling to the floor multiple occasions during clinches.
Parker finished the stronger, but multiple periods were difficult to score. Nevertheless, ex-champion the boxing analyst - providing analysis for Dazn - had it significantly in favor for the challenger, giving Buatsi just a single round.
The victor advances, but with the presence of heavy hitter David Benavidez, and Russian star Bivol leading the category, the road to world glory - based on this performance - still seems difficult.
Ricky Hatton Tribute Inspires Local Rivalry Battle
In the secondary fight, Lyndon Arthur defeated Bradley Rea by close verdict in a outstanding Manchester vs Manchester battle to secure the continental belt.
The arena became quiet for a deeply poignant homage ahead of the contest as ten bells tolled in remembrance of local hero Hatton, who succumbed at age 46 in last month.
It was the premier televised boxing event in the urban center since the passing of Hatton. As the concluding sound disappeared, the quiet transitioned to a shout of "only one Ricky Hatton".
The competition within the ring reflected the sentiment. The eventual winner was sent to the canvas by a significant blow flush on the jaw in the early round, getting up unsteadily to his position on the referee's count.
But the Manchester United-red equipment of the fighter soon came forward again. On the opposite side, the opponent - in rival City blue - was marked up quickly, heavy swelling developing under his orbital area as the pair landed hard punches.
Rea, twenty-seven, landed power punches but Arthur, 34, responded in kind with effective uppercuts as the action rarely dropped over twelve rounds.
The victor edged the result with judges scorecards of draw, close margin and wider gap, but both fighters were persistent and courageous, everything their hero Hatton embodied.
